Now that we have access to space, the easiest way to prove the Earth is spherical is to leave it and view it from a distance. Astronauts and space probes have done just that. Every picture of Earth ever taken shows only a circular shape, and the only geometric solid which looks like a circle from any direction is a sphere.

For a very long time people have considered the Earth to be flat. Why throw away years of culture and tradition based on a few pictures using advanced technology that very few have seen with their own eyes? Have you or anyone you know personally seen the Earth is round, and not just a photograph?

If you ever read hitchhiker's guide the galaxy you will learn the concept of filtered perception. Quite simply are senses often deceive us. Bias, prejudice, etc. Just use your favorite search engine and search "optical illusions." You'll find many.

II. Rebuttal of Con's arguments

"Every picture of Earth ever taken shows only a circular shape, and the only geometric solid which looks like a circle from any direction is a sphere." Con

Yes, but this is only a picture. The picture could have been altered or forged. There is also some doubt whether we landed on the moon.

"For a very long time people have considered the Earth to be flat. Why throw away years of culture and tradition based on a few pictures using advanced technology that very few have seen with their own eyes?"

Are you seriously implying that you would rather believe people from hundreds of years ago, who have never been in space, rather then the austronauts today, who HAVE been in space? Who have actually SEEN Earth from a distance? Wouldn't it be more ideal to believe the people with evidence, rather then the people without?

And as for your argument stating that the photograph could have been forge, may I ask you, what benefits would NASA gain from claiming false information about the world's shape?

One of the oldest proofs of the Earth's shape, however, can be seen from the ground and occurs during every lunar eclipse. The geometry of a lunar eclipse has been known since ancient Greece. When a full Moon occurs in the plane of Earth's orbit, the Moon slowly moves through Earth's shadow. Every time that shadow is seen, its edge is round. Once again, the only solid that always projects a round shadow is a sphere.

"And as for your argument stating that the photograph could have been forge, may I ask you, what benefits would NASA gain from claiming false information about the world's shape?" Con

Taking credit for something they didn't accomplish.

"One of the oldest proofs of the Earth's shape, however, can be seen from the ground and occurs during every lunar eclipse. The geometry of a lunar eclipse has been known since ancient Greece. When a full Moon occurs in the plane of Earth's orbit, the Moon slowly moves through Earth's shadow. Every time that shadow is seen, its edge is round. Once again, the only solid that always projects a round shadow is a sphere." Con

Filtered perception.

The Earth is flat. The vast majority of people believed this for a very long time.

You don't have to go into outer space to prove that the earth is spherical guys :)

In fact, we've known that the earth is not flat for a LONG time now.
Eratosthenes was a greek scholar that lived in 275-194 B.C. in Alexandria (Egypt). He was able to use simple trigonometry to calculate the radius and diameter of the earth over 2290 years ago.

Different states in the U.S.A wouldn't have different timezones if the earth was flat. Heck! The earth wouldn't have a center of gravity if it wasn't a sphere! The moon wouldn't be able to orbit us!

The idea that we needed to go into outer space in order to prove that the earth was not flat is just silly.
The earth is undoubtedly round...ish :P

An oftentimes used myth to discredit the Old Earth and it's inhabitants, but it's fundamentally untrue. The Greeks knew the world was round, The Romans knew it, The Persians knew it, many people knew it. There's a classic, simple experiment, which the ancient Greeks have come up with, where you look off into the horizon, and see the mast of a ship well before you see the rest of the ship. In fact, one of the earliest, and one of the most accurate measurements of the circumference of the Earth was achieved by a Greek in Egypt under the name of Eratosthenes of Cyrene, around 200 BC.

His measurement was incredibly accurate, with a margin of error of 1.6% (66 km), which is simply amazing considering it was 2 millennia ago. To not go into the mathematics he used, his measurements would have been impossible if the Earth were flat. He also calculated the Earth's tilt with amazing accuracy, against something that would've been impossible without a round earth.

The Pros argument that it's a part of culture, therefore legitimate, is ridiculous. The burning of witches and heretics was a staple of the times, but I don't seriously expect the Pro to argue in favor of those two things.